{ inputs, ... }: { perSystem = { system, lib, pkgs, ... }: { packages = let fnx = inputs.fenix.packages.${system}; stable-toolchain = fnx.fromToolchainFile { file = inputs.self + "/rust-toolchain.toml"; # See also `rust-toolchain.toml` sha256 = "sha256-sqSWJDUxc+zaz1nBWMAJKTAGBuGWP25GCftIOlCEAtA="; }; in { inherit stable-toolchain; dev-toolchain = fnx.combine [ stable-toolchain # use the nightly rustfmt because we use nightly features fnx.complete.rustfmt ]; }; }; }